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TOPIC: Insulation Concerns

New Metal Roof concerns

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I have a brand new home with a 5v metal roof. The contractor used 1x4 strips across the rafters and attached the metal directly to these then the insulation was rolled in and my tongue and groove ceiling was installed. I am concerned that I will have major issues with condensation and possible mold since there was not any plywood, underlayment or vapor barrier used. I do have soffits, ridge vent with no mesh and completely open ends, no rakes etc... I am thinking about having the roof re-done to add the other installation layers you have mentioned in these posts. What is your opinion? How likely is it that I will have problems in the future and possible damage to my ceiling as well?
Guest User

10/25/2008
The condensation issue remains to be seen. It is possible that you will not have any. We put metal on some huge buildings (churches) that is of open purlin construction. We put vinyl faced insulation over the purlin and the metal over that. In this case, your 1x4's is the same thing as our purlins. If there are any open places in the insulation or tears in the vinyl face, then you can have a problem with condensation in that area. If it is a large opening, then you can have a problem in a large area. On new home construction, if I have any input(which usually I do) I have been able to talk the builder/owner out of an open purlin situation. A solid deck goes a long way in helping with condensation. On buildings well insulated and with a solid deck we have not had any condesation issues. [email protected]
Guest User

10/26/2008
Wade is spot on of course. I would also suggest taking steps to avoid excessive humidity inside the home -- minimize houseplants, no ventless gas stoves, make sure all plumbing and exhaust fans and dryer are vented outside. Also, during cooler seasons, keep the fan on your hvac system running continuously. Todd Miller
Todd Miller
Isaiah Industries, Inc.

10/26/2008
Even though this is a new construction and a condensation problem is not evident yet, if this was your house, would you leave it as is and see if there is a problem or have the roof re-done with a solid deck now? What percent chance is there that a condensation problem will occur?
Guest User

10/27/2008
My house? I'd want the decking and underlayment Todd Miller
Todd Miller
Isaiah Industries, Inc.

10/28/2008
Hello Wade, Since my last question, the condensation concerns have been validated in a big way! I have actually had a stream of water run out one of my light fixtures due to condensation. I have cut two holes in my sheetrock in my upstairs closet to check condensation and it is unbelievable. I am getting ready to have a new roof put on with underlayment and 30# felt but I have leaned of another issue on which I need help. My contractor used 2 x 10 rafters and since the R38 batts are 9" thick and then the baffel on top of that, there is basically no air space. The insulation was also installed incorrectly in that the tabs were not put on the outside of the rafters so there are breaks in the barrier. Do you have any suggestion on what can be done to fix these issues from the roof side?
Guest User

12/17/2008
I would suggest a solid deck. As has been stated here before, the mass of the decking itself has insulation capabilities. With a solid deck and a good underlayment like Tamko's Metal and Tile Underlayment you will go a long way in curing the problem with condensation.
Guest User

12/18/2008
Have you physically checked for a ridge vent material? Or is this just what the contractor told you? Are soffits vented properly? you need air to travel from the soffit to the peak freely. This is what the baffle is for. If there was careless installation the baffle might not go into the soffit area far enough and will stop air flow. Just by putting a deck on top along with 30# felt does not mean you are correcting the possible air flow issues. It sounds like you have a cathedral ceiling so the baffles need to travel from the bottom. I have also seen insulation installed with the tabs inside the rafters not lead to any problems
Guest User

12/18/2008
P.s. it might be easier to pull a roof panel off to look at the air flow and condinsation problems
Guest User

12/18/2008
Thanks all Todd Miller
Todd Miller
Isaiah Industries, Inc.

12/18/2008
I have actually removed two sections of drywall from inside my closets and have seen and felt the condensations, insulation slammed against the metal, incomplete baffels and no airflow first hand. I have had one builder suggest building the rafters up with 2x6's to get the ventalation needed and correct the baffels then add a solid deck and 30# felt. What do you guys think of this?? I am attaching a engineer's report I had doen on all the issues for you to see.
Guest User

1/15/2009
This is clearly a condensation issue due to imprpoer ventilation. Before you throw good money over bad it seems that the proper insulation and venting would potentially fix your problem. The 1x4 purlin system may not be ideal but it is acceptable.
Guest User

1/15/2009
What is your suggestion for getting proper ventilation and insulation with a 2x10 rafter and 13" of R38 insulation plus baffels? If we don't build up the rafters isn't the only other solution to use a thinner insulation like syrofoam so we can get the 2" of airspace needed? If you have another suggestion I gladly welcome a cheaper solution! This has been a nightmare!
Guest User

1/15/2009
There are alot of problems. A big one is a bathroom fan venting into an attic space. You should vent that to the soffit area. Another is you dont have insulation in your entire attic space. A 2x10 should accept R-30 with baffles(I am not an expert in this field) If there isnt soffit vent or RIDGE VENT then you will have a problem. In the areas where there is a cathedral ceiling you can remove the sheeting one sheet at a time and install baffles and insulation from the outside. We are visiting the same suggestions in earlier post and I cannot offer any other advice so if you could 1) Verify soffit vent( you have no bottom end closure so it should vent ther at minimum 2)Is there baffles and insulation in cathedral area 3)Is ther RIDGE VENT? 4)Did you insulate entire attic area 5)Did you properly vent bath fan....
Guest User

1/15/2009